Personal computers utilize various mechanisms for receiving input. For example, many personal computers allow a keyboard, a mouse, a touchpad, or other such devices to provide input to the personal computer. Mobile personal computers, such as tablets, smart phones, laptops, and even many non-mobile computers, may incorporate a touch-screen that can receive input directly through contact, or near-contact, with the screen.
A stylus is one preferred implement for inputting information into a computer through the touch-screen. A stylus is typically shaped like a pen or a pencil and has a writing end designed for entering information, such as handwritten text or drawings, and a tail end that may function as an eraser to remove information from the touch-screen. However, the erase signal output from a stylus does not provide for a high degree of fineness, such as the ability to vary the size of the erased area or the ability to control the opacity of the erased area.